SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '241979d89161d11970966b6bff92a79136bb53839f23174384e7fa028b9ace2e' 
  AND token = 'UPK+qzVMJtlnlLL/tk7rRFI1xTHZGPUZH0e/x/yV6cI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}